JPS61273719A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the durability of the titled medium by providing a magnetic layer on one surface of a carrier and furnishing a layer contg. carbon black and specified titanium monoxide on the other surface. CONSTITUTION:A magnetic layer is formed on one surface of a carrier and a layer contg. carbon black and titanium monoxide treated with an isocyanate curing agent and having <=about 1Xm mean particle diameter is formed on the other surface. The titanium monixide is preferably added by about 0.5-70wt% based on the carbon black. About 25-400pts.wt. carbon black is preferably used with 100pts.wt. binder consisting of cellulose resin, polyester resin, a vinyl chloride-vinyl acetate copolymer, polyurethane resin, etc. Consequently, the durability of the magnetic layer is remarkably improved and a magnetic recording medium having excellent traveling property and traveling stability can be obtained.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、例えばビデオテープ、オーディオテーフ等の
磁気テープ又はフロッピーディスク等の磁気ディスクと
いった磁気記録媒体に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium such as a magnetic tape such as a video tape or an audio tape, or a magnetic disk such as a floppy disk.

〔従来技術とその問題点〕[Prior art and its problems]

近年、例えば家庭用ビデオテープレコーダ等の磁気記録
再生装置の分野での技術革新のスピードは急速なもので
あり、その技術革新の成果として高密度記録が達成され
つつある。In recent years, the speed of technological innovation in the field of magnetic recording and reproducing devices such as home video tape recorders has been rapid, and high-density recording is being achieved as a result of this technological innovation.

しかし、このような高密度記録は磁気記録再生装置の技
術革新のみによってもたらされるものではなく、これに
用いられる磁気記録媒体が磁気記録再生装置の技術革新
に対応して技術革新されたものでなければならない。However, such high-density recording is not brought about only by technological innovations in magnetic recording and reproducing devices; the magnetic recording media used for this must also be technologically innovated in response to technological innovations in magnetic recording and reproducing devices. Must be.

このような観点より、従来では、例えば磁気テープの非
磁性支持体であるベースフィルムは、その表面が平滑性
に富んでいるものが良いと言われている。From this point of view, it has conventionally been said that, for example, a base film that is a nonmagnetic support for a magnetic tape should have a surface that is highly smooth.

しかし、平滑性に富んだベースフィルムに磁性層を設け
た磁気記録媒体は、耐摩耗性が悪い等の耐久性の点に問
題があり、又、走行安定性も悪い等の欠点がある。However, magnetic recording media in which a magnetic layer is provided on a highly smooth base film have problems in terms of durability such as poor abrasion resistance, and also have drawbacks such as poor running stability.

そこで、このような欠点を解決する為に、磁性層と反対
側のベースフィルム面にいわゆるバックコート層を構成
することが提案（特開昭５９−５４２８．５９−５４２
９．５’ｌ−５４３０号公報）されている。Therefore, in order to solve this problem, it was proposed to form a so-called back coat layer on the side of the base film opposite to the magnetic layer (Japanese Patent Laid-Open No. 59-5428.59-542).
9.5'l-5430).

ところが、これら提案のものにあっても充分満足できる
ものではなく、例えば耐久性、さらには静電気の帯電の
問題が残されている。However, even these proposals are not completely satisfactory, and problems such as durability and electrostatic charging remain.

〔発明の開示〕[Disclosure of the invention]

本発明者は、いわゆるバックコート層の手段で高密度記
録に対、応できる磁気記録媒体を提供しようとする技術
思想は望ましいものではあるという観点に立ちながらも
、従来のバックコート層の構成された磁気記録媒体には
何故耐久性等の特性において欠点が残されているのかを
研究した結果、バックコート層の組成によってこれらの
特性が大きく影響されることに気付き、そこでバックコ
ート層をどのような構成にするかの研究を続行した結果
、このいわゆるバックコート層中にカーボンブラックと
イソシアネート系硬化剤で処理された平均粒径約１μｍ
以下の一酸化チタンとを含む磁気記録媒体は、従来のも
のよりも大巾に耐久性が改善されることを見い出した。The present inventor believes that the technical idea of providing a magnetic recording medium that can handle high-density recording by means of a so-called back coat layer is desirable, but the inventor believes that the conventional structure of the back coat layer is As a result of researching why magnetic recording media still have shortcomings in characteristics such as durability, they realized that these characteristics are greatly affected by the composition of the backcoat layer. As a result of continuing research into the composition of
It has been found that magnetic recording media containing the following titanium monoxide have significantly improved durability compared to conventional media.

尚、上記のようなイソシアネート系硬化剤で処理された
一酸化チタンは、例えば−酸化チタンとインシアネート
系硬化剤、例えば日本ポリウレタン工業■製のコロネー
トＨＬ１武田薬品工業■製のＤ−１０３Ｈ等とを、その
約２倍量程度のトルエン等の溶剤中に入れて混合分散、
望ましくは数時間程度加熱分散させることによって得ら
れるものであり、そして−酸化チタンに対して約１〜１
００重量％のイソシアネート系硬化剤が反応しているよ
うになったものが特に望ましい。Incidentally, titanium monoxide treated with the above-mentioned isocyanate-based curing agent is, for example, -titanium oxide and an incyanate-based curing agent, such as Coronate HL manufactured by Nippon Polyurethane Industry ■, D-103H manufactured by Takeda Pharmaceutical Company Limited, etc. is mixed and dispersed in about twice the volume of a solvent such as toluene.
It is preferably obtained by heating and dispersing for several hours, and has a content of about 1 to 1 based on titanium oxide.
Particularly desirable is one in which 00% by weight of the isocyanate curing agent is reacted.

ここで、−酸化チタンの平均粒径が約１μｍ以下のもの
としたのは、１μｍを越えてあまりに大きすぎる一酸化
チタンを用いた場合には、表面性が悪くなり、電磁変換
特性の低下や粉落ちが著しくなるからである。Here, the reason why the average particle size of the titanium oxide is set to be approximately 1 μm or less is because if titanium monoxide exceeding 1 μm is used, the surface properties will deteriorate and the electromagnetic conversion characteristics may deteriorate. This is because powder falls off significantly.

尚、この−酸化チタンの添加量は、カーボンブラックに
対して約０．５〜７０重量％位であることが望ましく、
つまり一酸化チタンの量が０．５重量％よりはるかに少
なすぎては一酸化チタン添加による耐久性改善の効果が
弱く、又、逆に７０重量％を越えて多くなりすぎると耐
久性向上が低下し始め、又、静電気の帯電防止効果も低
下し、電磁変換特性も低下し始める傾向があるからであ
る。The amount of titanium oxide added is preferably about 0.5 to 70% by weight based on the carbon black.
In other words, if the amount of titanium monoxide is much less than 0.5% by weight, the effect of improving durability by adding titanium monoxide will be weak, and conversely, if the amount is too much, exceeding 70% by weight, the durability will not be improved. This is because there is a tendency for the electromagnetic conversion characteristics to begin to deteriorate, as well as for the antistatic effect of static electricity to deteriorate.

又、カーボンブラックの含有量としては、例えば繊維素
樹脂、ポリエステル樹脂、塩化ビニル−酢酸ビニル共重
合体、ポリウレタン樹脂等の用いられるバインダー１０
０重量部に対して約２５〜４００重量部位であることが
望ましい。In addition, the content of carbon black may vary depending on the binder used, such as cellulose resin, polyester resin, vinyl chloride-vinyl acetate copolymer, polyurethane resin, etc.
Preferably, the amount is about 25 to 400 parts by weight relative to 0 parts by weight.

又、−酸化チタンは、その平均粒径が約１μｍ以下のも
のであれば良いが、さらに望ましくは約０．０１μｍ以
上のものであることが好ましい。The titanium oxide may have an average particle size of about 1 μm or less, more preferably about 0.01 μm or more.

又、上記−酸化チタン及びカーボンブラックを含む、い
わゆるバックコート層は、その厚みが約０．３〜４μｍ
程度のものであることが望ましい。Moreover, the so-called back coat layer containing titanium oxide and carbon black has a thickness of about 0.3 to 4 μm.
It is desirable that it be of a certain degree.

〔実施例１〕 支持体であるベースフィルムの表面側には所定の磁性塗
料を、かつ裏面側には、カーボンブラック１００重量部
、硝化綿６０重量部、ポリウレタン樹脂４０重量部、コ
ロネー）Ｉ（Ｌで表面処理された平均粒径約０．０１μ
ｍの一酸化チタン０．８重量部、ステアリン酸５重量部
、コロネートＨＬ１５重量部、シクロヘキサ７７８５０
重量部を充分に混練して得た塗料を、乾燥後におけるこ
の塗膜層厚が約０．８μｍ厚となるよう塗布し、そして
８０℃で４０時間の硬化反応といった所定の工程を経て
、表面側には磁性層が、裏面側にはカーボンブラックと
コロネートＨＬで表面処理された一酸化チタンとを含む
いわゆるバックコート層が形成された磁気テープ等の磁
気記録媒体を得る。[Example 1] A predetermined magnetic paint was applied to the front side of the base film as a support, and 100 parts by weight of carbon black, 60 parts by weight of nitrified cotton, 40 parts by weight of polyurethane resin, and Coronet) I ( Average particle size of surface treated with L is about 0.01μ
m titanium monoxide 0.8 parts by weight, stearic acid 5 parts by weight, Coronate HL 15 parts by weight, cyclohexa 77850
The paint obtained by thoroughly kneading the parts by weight is applied so that the coating layer thickness after drying is approximately 0.8 μm, and then subjected to a prescribed process such as a curing reaction at 80°C for 40 hours to form a surface. A magnetic recording medium such as a magnetic tape is obtained in which a magnetic layer is formed on the side and a so-called back coat layer containing carbon black and titanium monoxide surface-treated with Coronate HL is formed on the back side.

〔実施例２〕 実施例１において、−酸化チタンとしてその平均粒径が
約０．０３μｍのものを１０重量部用いて同様に行ない
、磁気記録媒体を得る。[Example 2] The same procedure as in Example 1 was carried out using 10 parts by weight of titanium oxide having an average particle size of about 0.03 μm to obtain a magnetic recording medium.

〔実施例３〕 実施例１において、−酸化チタンとしてその平均粒径が
約０．１３μｍのものを３０重量部用いて同様に行ない
、磁気記録媒体を得る。[Example 3] The same procedure as in Example 1 was carried out using 30 parts by weight of titanium oxide having an average particle size of about 0.13 μm to obtain a magnetic recording medium.

〔実施例４〕 実施例１において、−酸化チタンとしてその平均粒径が
約０．９８μｍのものを７０重量部用いて同様に行ない
、磁気記録媒体を得る。[Example 4] The same procedure as in Example 1 was carried out using 70 parts by weight of titanium oxide having an average particle size of about 0.98 μm to obtain a magnetic recording medium.

〔比較例１〕 実施例２において、コロネー）ＨＬで表面処理されてい
ない一酸化チタンを用いて同様に行ない、磁気記録媒体
を得る。[Comparative Example 1] A magnetic recording medium is obtained by carrying out the same procedure as in Example 2 using titanium monoxide which has not been surface-treated with Coronae HL.

〔比較例２〕 実施例２において、−酸化チタンを用いずに同様に行な
い、磁気記録媒体を得る。[Comparative Example 2] A magnetic recording medium is obtained by carrying out the same procedure as in Example 2 without using -titanium oxide.

〔比較例３〕 実施例２において、コロネー）ＨＬで表面処理された一
酸化チタンの代りにコロネー）ＨＬで表面処理された二
酸化クロムを用いて同様に行ない、磁気記録媒体を得る
。[Comparative Example 3] A magnetic recording medium is obtained by carrying out the same procedure as in Example 2 using chromium dioxide whose surface was treated with Coronae) HL instead of titanium monoxide whose surface was treated with Coronae) HL.

〔比較例４〕 実施例４において、コロネー）ＨＬで表面処理されてい
ない一酸化チタンを用いて同様に行ない、磁気記録媒体
を得る。[Comparative Example 4] A magnetic recording medium is obtained by carrying out the same procedure as in Example 4 using titanium monoxide which has not been surface-treated with Coronae HL.

〔比較例５〕 実施例３において、−酸化チタンとしてその平均粒径が
約１．９μｍのものを用いて同様に行ない、磁気記録媒
体を得る。[Comparative Example 5] The same procedure as in Example 3 was carried out using -titanium oxide having an average particle size of about 1.9 μm to obtain a magnetic recording medium.

〔特性〕〔Characteristic〕

上記各側で得た磁気テープのような磁気記録媒体を磁気
記録再生装置に装着して５００回繰り返し走行テストを
行ない、走行後の傷付具合、粉落具合、摩擦係数を調べ
ると表に示す通りである。The magnetic recording media such as the magnetic tapes obtained on each side above were mounted on a magnetic recording/reproducing device, and a running test was conducted 500 times to examine the degree of damage, dusting, and coefficient of friction after running, as shown in the table. That's right.

又、電磁変換特性（カラーＳ／Ｎ）を調べると表に示す
通りである。Further, the electromagnetic conversion characteristics (color S/N) are as shown in the table.

表 ・傷付具合側における◎印は傷付全く無、○印は傷付少
し有、Δ印は傷付かなり有、Ｘ印は傷付非常に多。On the front/scratches side, ◎ marks have no scratches, ○ marks have some scratches, Δ marks have a lot of scratches, and X marks have very many scratches.

・粉落具合欄）ておける◎印は粉落全く無、○印は粉落
少し有、Δ印は粉落かなり有、Ｘ印は粉落非常シ；多。・In the powder removal condition column), ◎ indicates no powder, ○ indicates some powder, Δ indicates considerable powder, and X indicates very much powder.

この表゛かられかるように、いわゆるバックコート層中
にイソシアネート系硬化剤で処理された一酸化チタンが
含まれていない場合には傷付や粉落が酷く、磁性層の耐
久性に劣っており、かつ走行性も悪く、又、イソシアネ
ート系硬化剤で処理された一酸化チタンが含まれていて
もその平均粒径が１μｍを越えて大きすぎる場合には粉
落が酷く、磁性層の耐久性に劣っており、さらにはカラ
ーＳ／Ｎが悪いといったように電磁変換特性も悪く、か
つ走行性も悪く、又、いわゆるバックコート層中の一酸
化チタンがインシアネート系硬化剤で処理されていない
場合には、傷付ヤ粉落具合が少々有り、又、摩擦係数も
増大するといったように走行性も悪いのに対し、本発明
に係るものは、傷付や粉落もなく、かつ摩擦係数も小さ
くて走行性が良く、さらにはカラーＳ／Ｎが良いといっ
たように電磁変換特性も良いものである。As can be seen from this table, if the so-called back coat layer does not contain titanium monoxide treated with an isocyanate-based hardener, scratches and flaking will be severe, and the durability of the magnetic layer will be poor. Moreover, even if titanium monoxide treated with an isocyanate-based hardening agent is contained, if the average particle size is too large (over 1 μm), powder drop is severe and the durability of the magnetic layer is reduced. Furthermore, the electromagnetic conversion characteristics are poor, such as poor color S/N, and the running properties are poor.Also, the titanium monoxide in the so-called back coat layer is treated with an incyanate-based curing agent. If there is no damage, there will be some scratches and powder shedding, and the friction coefficient will also increase, resulting in poor running performance.In contrast, the product according to the present invention has no scratches or powder shedding, and has low friction. It has a small coefficient and good runnability, and also has good electromagnetic conversion characteristics such as a good color S/N ratio.

〔効果〕〔effect〕

本発明は磁性層と反対側の支持体の面にカーボンブラッ
クとインシアネート系硬化剤で処理された平均粒径約１
μｍ以下の一酸化チタンとを含む層を構成したので、傷
付や粉落がほとんどなくなり、磁性層の耐久性が著しく
向上し、又、摩擦係数が小さくて走行性及び走行安定性
に優れており、さらにはカラーＳ／Ｎといった電磁変換
特性が良い磁気記録媒体を提供することができる。In the present invention, the surface of the support opposite to the magnetic layer is treated with carbon black and an incyanate-based hardener.
Since the layer contains titanium monoxide of less than μm, there is almost no scratching or powder falling off, and the durability of the magnetic layer is significantly improved.In addition, the coefficient of friction is small, resulting in excellent running performance and running stability. Furthermore, it is possible to provide a magnetic recording medium with good electromagnetic conversion characteristics such as color S/N.

Claims (1)

【特許請求の範囲】[Claims] 支持体の一面側に磁性層を、かつ他面側にカーボンブラ
ックとイソシアネート系硬化剤で処理された平均粒径約
１μｍ以下の一酸化チタンとを含む層を構成したことを
特徴とする磁気記録媒体。A magnetic recording comprising a magnetic layer on one side of a support, and a layer containing carbon black and titanium monoxide with an average particle size of about 1 μm or less treated with an isocyanate hardener on the other side. Medium.